A situation came up in my session where a fighter used his Shield Master Shove feature to shove a Giant Crocodile that was currently restraining another PC using it's bite+grapple ability.
I did a quick check at the time and did not find anything related to shove, although in the grappled condition description it states:
The condition also ends if an effect removes the grappled creature from the reach of the grappler or grappling effect, such as when a creature is hurled away by the thunderwave spell.
I ruled at the time that a shove would count in a similar way to being "hurled away" however I wasn't sure and said I would find more concrete information for the future.
I have searched high and low for somebody else asking this specific question but have yet to find it. I saw some reference to a Jeremy Crawford tweet about involuntary movement and grappling however I am unable to find it.
If a third party "shoves" a creature that is grappling another, does it only shove the grappler away, or does it move both the grappler and grappled?
I drew a diagram:
(A related question is about the grappled creature shoving their grappler; this question relates to if a third party shoves the grappler instead, so it's not a duplicate.)
Best Answer
Yes, it does break the grapple (if you end up outside of its reach)
Thunderwave says:
Shoving uses a similar wording:
Assuming you opponent only has a reach of 5 foot (and did not start in your space), shoving should fulfill the clause in the Grappled condition in the same way as Thunderwave would:
It's fine if a third party does the shoving (assuming they can shove in the right direction). The above quote does not state that the grappled creature must cause the effect, only that the effect must remove "the grappled creature from the reach of the grappler or grappling effect".
Also note, moving either the grappler or the grappled creature can count as an effect that "removes the grappled creature from the reach of the grappler or grappling effect" (i.e. in the same way that you can remove someone from danger by eliminating the danger instead of actually moving them). Also see this answer here about the graplee taking the shoving action.
In the querent's diagram, if the character taking shoving action pushed the Crocodile down and to the left (which is technically also 'away' from himself, but check with your DM), it should be enough to separate the two opponents (assuming you are using a grid and/or don't charge extra for the diagonal movement - again, check with your DM)